Structure of inline skates

ABSTRACT

The present invention relates generally to an improved structure of inline skates, which provides a cushion, a wheel with a gearwheel on its side, and a pawl assembly. By pressing down the weight, the wheel with gearwheel on its side occludes the pawl assembly, which stops the wheel with gearwheel on its side from rolling one-wayly. Thereby, the improved structure of inline skates is more ergonomic and exercise injuries can be prevented. In addition, a brake is provided for providing shock absorption and more powerful acceleration. Besides, automatic support upright is also provided for avoiding tumbles.

FIELD OF THE INVENTION

The present invention relates generally to inline skates, and particularly to inline skates that combining a one-way roll stop device and a cushion for providing the inline skates with superior braking effect during sliding as well as with more forceful acceleration holds. Thereby, an improved structure of inline skates with ergonomics, exercise-injury prevention, and comfort is provided.

BACKGROUND OF THE INVENTION

Inline skating is a rising roller-skating exercise. To date a variety of types has developed including mainly recreational, figure, cross-country, acrobatic, and speed. Special structures are designed for cross-country and speed inline skates to meet their speed demands or requirements by special environments. In addition, extraordinary and long-term trainings are required to handle and use them appropriately. The basic structure and function thereof similar to recreational inline skates, details of the inline skates of these types are not described here. In the following, recreational, figure, and acrobatic inline skates are described in detail.

First, for a recreational inline skate, the structure thereof includes a boot, a base under the boot, and a plurality of wheels adapted on the base. There is no front brake pad. When the left leg slides, it is necessary to use the right leg to press the ground and push backwards in the direction slightly deviating from the direction of sliding then a forward force for the left leg is given. Owing to the larger wheel diameter with the longer span, it is laborious to press and push slantingly both legs alternately for maintaining sliding for a long time. In addition, it violates ergonomics as well. Besides, recreational inline skates do not provide effective braking disposal. Some brands add rear brake pads behind the roller skates. While braking, the player has to put forth his strength to raise his feet upwards with his ankles pushed downwards so that the rear brake pads under the ankles can produce friction with the ground. By doing this, slight braking effect is attained. However, the braking effect is very poor, and the braking action violates ergonomics as well. Furthermore, the rear brake pads tend to make both legs stuck with and bump against each other and consequently make the player stumble when he alternates his legs to slide or when he comers (forward or backward crossovers). Thereby, most players disassemble the rear brake pads by themselves, which makes the rear brake pads exist in name only.

Moreover, for a figure inline skate, a front brake pad is adapted at the first-wheel position of a recreational inline skate, and all wheels are shrunk and arranged behind the front brake pad. Hence, the figure inline skate slides slower and unstable. When sliding forward, the center of gravity leans forward. Slight incaution results in touch of the front brake pad on the sliding leg on the ground, which is very dangerous because it will cause the player trip forward.

As for an acrobatic line skate, no brake is adapted thereon because a brake device that is like the one on a recreational or a figure inline skate obstructs absolutely acrobatic movements and thereby results in danger. However, it does not mean that an acrobatic inline skate need not a brake device. In fact, tumbles when wearing acrobatic inline skates occur frequently. Some severe injuries even happened.

To sum up, various current inline skates cannot provide an effective and safe brake device. A special braking skill, that is, T-stop, refers to turning aside and opening both legs abruptly during sliding to make both legs perpendicular to the direction of sliding for attaining braking effect. However, this skill needs long-term practices. Slight incaution tends to result in tumble and accidental injuries such as scrapes, collision injuries, and sprains. Besides, the skill violates ergonomics. In addition to ease of wear on the inline skates, T-stop is not applicable in all fields. If the field is slightly slippery, unsmooth, or has too much grip, falling over tends to happen. Thereby, improved brake device of inline skates is desired for solving inconveniences in operations and problems of frequent exercise injuries.

Owing to the drawbacks and imperfections of inline skates described above, the present invention provides inline skates complying with ergonomics, being exercise-injury preventive, shock absorptive, and comfortable. In addition, the inline skates according to the present invention provide multiple brakes as well as providing more powerful acceleration. By supporting upright automatically, the inline skates according to the present provide active safety for players.

SUMMARY

An objective of the present invention is to provide an improved structure of inline skates, which can achieves superior braking effect in a manner complying ergonomics. In addition, the inline skates according to the present invention can support upright automatically on the go for preventing tumbles. Thereby, exercise injuries are reduced or avoided accordingly, and active safety is provided.

Another objective of the present invention is to provide an improved structure of inline skates, which can provide effectively more forceful acceleration holds as well as shock-absorbing capability for comfort. Thereby, the operation quality of the inline skates is improved.

In order to achieve the objectives and effects described above, the present invention provides an improved structure of inline skates, which includes a boot, a base, a wheel set, one or more one-way roll stop devices, and one or more cushions. When the base is pressed, the wheels of the wheel set are pressed accordingly. The cushion eases the stress through compression thereof. When the cushion compresses, it drives said one or more one-way roll stop devices to step rolling. Thereby, braking effect and an acceleration hold are provided. In addition, shock-absorbing effect is provided as well by the cushion.

In order to make the structure and characteristics as well as the effectiveness of the present invention to be further understood and recognized, the detailed description of the present invention is provided as follows along with preferred embodiments and accompanying figures.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a three-dimensional schematic diagram according to a first preferred embodiment of the present invention;

FIG. 2 shows an explosion view according to the first preferred embodiment of the present invention;

FIG. 3 shows a side view according to the first preferred embodiment of the present invention;

FIG. 4 shows an action schematic diagram of a front wheel according to the first preferred embodiment of the present invention;

FIG. 5 shows a resistive action schematic diagram of a front wheel according to the first preferred embodiment of the present invention;

FIG. 6 shows a schematic diagram according to a second preferred embodiment of the present invention;

FIG. 7 shows a schematic diagram according to a third preferred embodiment of the present invention; and

FIG. 8 shows a schematic diagram according to a fourth preferred embodiment of the present invention.

DETAILED DESCRIPTION

FIGS. 1 to 3 show an improved structure of inline skates according to a first preferred embodiment of the present invention. The inline skate 100 includes a boot 10, a base 20, a wheel set 30, a one-way roll stop device 40, and a cushion 50.

The base 20 is adapted on the bottom of the boot 10, and comprises one or more connection plates 21 and two side plates 22 adapted under both sides of the connection plate 21, respectively. At the front end of the side plate 22, a long pivotal bore 221 is adapted. Behind and above the long pivotal bore 221, two securing holes 222 are adapted. In addition, behind the long pivotal bore 221, three pivotal holes (not shown in the figures) are adapted for pivoting the wheel set 30. The wheel set 30 includes a front wheel 31, two center wheels 32, and a rear wheel 33. The front wheel 31 is adapted between said two long pivotal bores 221 by means of a screw bolt assembly 34. The center wheels 32 and the rear wheel 33 are adapted between corresponding pivotal holes of the side plates 22 behind the long pivotal bores 221 by means of screw bolt assemblies 35, respectively.

The one-way roll step device 40 includes a gearwheel 41 and a pawl assembly 42. The gearwheel 41 is an annular-shaped slice and is smaller slightly in diameter than the front wheel 31. It is manufactured integrally and is mounted pivotally at the centers on both sides of the front wheel 31. Alternatively, the annular-shaped slices can be secured at the centers on both sides of the front wheel 31. First gearteeth 411 with one-way hook-shaped teeth are adapted on the periphery of the gearwheel 41. The pawl assembly 42 includes an elastic plate 421 and pawls 422 on both sides under the elastic plate 421. The elastic plate 421 is roughly a U-shaped plate. The shape here according to a preferred embodiment is used for description but not for limiting its scope. On both ends of the elastic plate 421, two wing plates 423, which extend upwards and outwards, are adapted. One or more sets of a plurality of second gearteeth 425 are adapted on the pawl 422, which has two long bores 424. The pawl assembly 42 are secured on the securing bores 222 by passing screw bolt assemblies 426 through the long bores 424 and the securing bores 222, and the wing plates 423 of the elastic plate 421 connect against the underside of the corresponding connection plate 21 while making the second wheelteeth 425 of the pawls 422 correspond to the first wheelteeth 411 of the gearwheels 41. Thereby, the pawl assembly 42 can move up and down in the long bores 424 by means of the screw bolt assemblies 426. Moreover, because the elastic plate 421 has elasticity and can extend and compress, the pawl assembly 42 can have elastic cushion effect accordingly, which occurs when the gearwheel 41 is not locked but can slide freely.

The cushion 50 is adapted on one side of the side plates 22, respectively, including two sliding block and sleeve assemblies 51, two springs 52, two adjustment shafts 53, and two nuts. The sliding block and sleeve assembly 51 is an assembly with a sleeve 511 and a sliding block 512, which is a long block corresponding to the long pivotal bore 221 with a shorter length. A pivotal hole 514 is adapted at the lower end of the sliding block and sleeve assembly 51. The pivotal hole 514 is used for passing the screw bolt assembly 34 and securing the sliding block and sleeve assembly 51 on the side of the front wheel 31 with the sliding block 512 inset in the long pivotal bore 221. A trench 513 is adapted from the top of the sleeve 511 (as shown in FIG. 3), and is used for accommodating the spring 52 and the adjustment shaft 53. The spring 52 is put around the adjustment shaft 53, whose top end is secured on the connection plate 21. in addition, threads are adapted on the adjustment shaft 53 with two nuts 54 thereupon for confining the spring 52 between the trench 513 and the nuts 54. By adjusting the threading locations of the nuts 54, the cushioning force of the spring 52 can be adjusted accordingly. Hence, requirements by players with different weights or by various cushioning conditions can be met by adjustments at any time.

Please refer to FIG. 3. The first gearteeth 411 on gearwheel 41 of the one-way roll stop device 40 protrude opposite to the second gearteeth 425 on the pawl 422 of the pawl assembly 42. Besides, when the gearwheel 41 contacts with the pawl assembly 42, according to the rolling direction of the gearwheel 41, two statuses result including an occlusion and cease-rolling status, and a free-sliding and maintain-rolling status. When the one-way roll stop device 40 is adapted on the front wheel 31, it is installed to make the gearwheel 41 and the pawl assembly 42 in the free-sliding and maintain-rolling status when the gearwheel 41 rolls forwards, and in the occlusion and cease-rolling status when the gearwheel 41 rolls backwards. Thereby, when the one-way roll stop device 40 is adapted in the front wheel 31, it can stop the front wheel 31 from rolling if the front wheel 31 rolls backwards.

Please refer to FIG. 4. In general, when the inline skates slide forward, the weight of the player is distributed evenly on the front wheel 31, the two center wheels 32, and the rear wheel 33. In this scenario, the front wheel 31 maintains common operation condition, and the gearwheel 41 does not contact with the pawl assembly 42. Even if the player pushes downwards the front wheel 31, the front wheel 31 will not stop rolling forward. This is because when the inline skates move forwards, the front wheel 31, and hence the gearwheel 41, roll forwards as well. Thereby, the gearwheel 41 and the pawl assembly 42 are not occlusive. Through the elastic cushioning function of the pawl assembly 42, the gearwheel 41 and the pawl assembly 42 will be in the free-sliding and maintain-rolling status.

Please refer to FIG. 5. The braking function of the one-way roll stop device 40 adapted in the front wheel 31 is similar to the gearwheel in front of a general figure skate or to the brake pad in front of a conventional four-wheel skate, and is done by tipping toes while sliding backwards. If acceleration is desired, the back propelling leg uses the front wheel 31 to propel backwards. At the instant of propelling, the front wheel 31 rolls backwards. Thereby, when the player needs braking or acceleration, the front wheel 31 is pressed downwards. At this moment, the front wheel 31 rolls backwards. Because of downward pressure on the cushion 50 by weight, the gearwheels 41 on sides of the front wheel 31 occlude with the pawl assemblies 42 and rolling is stopped. Hence, the rolling of the front wheel 31 is stopped one-wayly. Thereby, braking effect or a hold for forward acceleration is provided. Consequently, when the front wheel 31 rolls forwards, if pressure is exerted downwards, the gearwheel 41 and the pawl assembly 42 are in the free-sliding and maintain-rolling status. On the other hand, when the front wheel 31 rolls backwards, if pressure is exerted downwards, the gearwheel 41 and the pawl assembly 42 are in the occlusion and cease-rolling status.

FIG. 6 shows a schematic diagram of an improved structure of inline skates according to a second preferred embodiment of the present invention, and is used for describing that a one-way roll stop device 40′ and a cushion 50′ are adapted on the rear wheel 33. The difference between the present embodiment and the previous embodiment is that the one-way roll stop device 40′ is adapted as stopping rolling while rolling forwards. That is, the directions of first gearteeth 411′ of a gearwheel 41′ and of second gearteeth 425′ of a pawl assembly 42′ are opposite to the directions of those adapted in the front wheel 31. Thereby, when a player needs braking or is about to fall down faceup carelessly, by pressing the rear wheel 33 downwards by his weight to some extent, the gearwheel 41′ on the side of the rear wheel 33 locks the pawl assembly 42′, and thus ceasing the rear wheel 33 from rolling forwards one-wayly. Accordingly, a braking force is attained for braking and a forward supporting reaction force is provided for avoiding falling down backwards. In addition, the baking effect according to the present embodiment is far superior to the braking effect of the rear brake pad in a recreational inline skate according to the prior art without the drawbacks and danger brought about by the latter.

FIG. 7 shows a schematic diagram of an improved structure of inline skates according to a third preferred embodiment of the present invention. The third preferred embodiment is provided on the basis of the first preferred embodiment described above. The gearwheel 41 and the pawl assembly 42 are adapted likewise. The difference is on the embodiment of the cushion 50. The side plates 22 of the base 20 are further divided into front side plates 23 on both sides. The back end of the front side plate 23 connects with the side plate 22, and the front end thereof is used for pivoting the front wheel 31. In addition, a penetrating trench 515 is adapted in the sleeve 511 of the cushion 50. In side the penetrating trench 515, a ring-stop surface 516, which is used for stopping the spring 52. When the adjustment shaft 53 passes through the penetrating trench 515, a nut 517 is used for securing. Thereby, the position of the front wheel 31 can be secured by means of the front side plate 23, the sleeve 511, and the adjustment shaft 53. Besides, the compression force of the spring 52 can be adjusted by adjusting the nuts 54. Moreover, the cushion 50 connects with the connection plate 21 in terms of a pivotal device 55. Thereby, the front wheel 31 can have even better shock-absorbing comfort.

FIG. 8 shows a schematic diagram of an improved structure of inline skates according to a fourth preferred embodiment of the present invention. The fourth preferred embodiment is provided on the basis of the third preferred embodiment described above. The fourth preferred embodiment adopts different device for embodying one or more one-way roll stop device 40A. The adjustment shaft 53 of the cushion 50 is adapted on a pivotal hole 24 in front of the side plate 22. The other end of the cushion 50 connects with the front wheel 31 and the front side plate 23 through a screw bolt assembly 34. However, a different device is adopted for embodying said one or more one-way roll stop device 40A. First, a plurality of surrounding arc-shaped holes 230 is adapted on the front side plate 23, and a pivotal hole 231 is adapted at the center of said plurality of surrounding arc-shaped holes 230. Besides, the one-way roll stop device 40A includes a side gearwheel 401 and a side pawl 402. The side gearwheel 401 is adapted inside the front wheel 31. The side pawl 402 has an annular body 402A, one side of which has one or more gearteeth 402B. Said one or more gearteeth 402B correspond to the side gearwheel 401, and can occlude with each other or slide freely. When the front wheel 31 rolls forward, said one or more gearteeth 402B slide freely with the side gearwheel 401. On the contrary, when the front wheel 31 rolls backwards, said one or more gearteeth 402B occlude with the side gearwheel 401. On the other side of the annular body 402A, a plurality of first stick-like parts 402D and a plurality of second stick-like parts 402E, both distributed annularly, are adapted. The first stick-like parts 402D are thicker than the second stick-like parts 402E, and a trench 402C is adapted on the end of each second stick-like part 402E. The plurality of surrounding arc-shaped holes 230 is larger than the plurality of first stick-like parts 402D and second stick-like parts adapted on one side of the annular body 402A of the side pawl 402. In addition, the side pawl 402 passes through the plurality of surrounding arc-shaped holes 230 adapted on the front side plate 23, and a second compression spring 407, a spacer 406, a first compression spring 405, a special-shaped spacer 404, and a hook ring 403 are slip on sequentially thereon. The hook ring 403 clips on a trench 402C. The inner radius of the spacer 406 is smaller than the outer radius of the circle surrounded by the first stick-like parts 402D, and the elastic force of the second compression spring 407 is smaller than that of the first compression spring 405. Thereby, a driving apparatus is defined to include a driver 408, the second compression spring 407, the spacer 406, the first compression spring 405, the special-shaped spacer 404, and the hook ring 403. Owing to the functions of the first compression spring 405 and the second compression spring 407, the annular body 402A of the side pawl 402 maintains tight contact with the front side plate 23 under normal conditions. In addition, the driver 408 is adapted on the side plate 22 and is adapted above the special-shaped spacer 404. When weight presses the connection plate 21, the cushion 50 is compressed accordingly, which makes the driver 408 close and contact the special-shaped spacer 404. Because the contact surface of the driver 408 on the special-shaped spacer 404 is an inclined plane 408A, when the driver 408 is pressed down, it will produce a pressing force on the special-shaped spacer 404 towards the front side plate 23. Nevertheless, because the inner radius of the spacer 406 is smaller than the outer radius of the circle surrounded by the first stick-like parts 402D, and the elastic force of the second compression spring 407 is smaller than that of the first compression spring 405, said pressing force towards the front side plate 23 will not compress the first compression spring 405, but, instead, will force the spacer 406 to compress the second compression spring 407 and thereby make the side pawl 402 move towards the side gearwheel 401. At this moment, if the front wheel 31 rolls backwards, the side gearwheel 401 will occlude with the side pawl 402 and the rolling is stopped one-wayly. On the contrary, if the front wheel 31 rolls forwards at the moment, due to deployment of the first compression spring 405, the side gearwheel 401 and the side pawl 402 slide freely.

From the description above, it is known that the present has at least the following effects and features:

-   1. If the cushion and the one-way roll stop device according to the     present invention are adapted in the front wheel, when the front     wheel is pressed to some extent while rolling backwards, the front     wheel has the capability of stopping rolling backwards and     one-wayly. If the cushion and the one-way roll stop device according     to the present invention are adapted in the rear wheel, when the     rear wheel is pressed to some extent while rolling forwards, the     rear wheel has the capability of stopping rolling forwards and     one-wayly. -   2. According to the present invention, if forward propelling is     desired by pressing backwards, because the propelling leg is pressed     downwards by weight and the front wheel is pushed backwards, which     is in a back-rolling status, thereby, back-rolling is stopped     one-wayly. Consequently, a hold for propelling forward that is more     powerful and more ergonomic is given. -   3. The operation of the braking function on the front wheel     according to the present invention is similar to the gearwheel in     front of a general figure skate or to the brake pad in front of a     conventional four-wheel skate, and is done by tipping toes while     sliding backwards. At this moment, the front wheel is pressed while     rolling backwards, thereby, a braking function that is more     ergonomic and safe is given. The braking effect of the rear wheel is     similar to the braking effect of the rear brake pad in a     recreational inline skate. When the player slides forwards, if he     puts forth his strength to raise his feet upwards with his weight     pushed downwards the rear wheel, at which moment the rear wheel is     pressed to some extent and rolling forward, a braking effect that     stops rolling forwards is attained. The baking effect is far     superior to the braking effect of the rear brake pad in a     recreational inline skate according to the prior art without the     drawbacks and danger brought about by the latter. -   4. As provided in the front and the rear wheels according to the     present invention, when the player steps forward, because of the     cushions adapted thereon, tiptoes and ankles are cushioned and     shock-absorbed. Thereby, ergonomic effect is attained. -   5. When the players is about to fall down forwards carelessly,     because the front wheel is pressed by weight while rolling     backwards, a braking force is given for stopping rolling backwards     and one-wayly. Thereby, the player is supported upright     automatically. When the players is about to fall down faceup     carelessly, because the rear wheel is pressed by weight while     rolling forwards, a braking force is given for stopping rolling     forwards. Thereby, the player is supported by the reaction force     upright automatically.

Accordingly, the present invention conforms to the legal requirements owing to its novelty, non-obviousness, and utility. However, the foregoing description is only a preferred embodiment of the present invention, not used to limit the scope and range of the present invention. Those equivalent changes or modifications made according to the shape, structure, feature, or spirit described in the claims of the present invention are included in the appended claims of the present invention. 

1. An improved structure of inline skates, comprising: a boot; a base, securing at the bottom of the boot, comprising one or more connection plates, and two side plates being adapted on both sides of the bottom of the connection plate, respectively with a plurality of pivotal holes thereon; a wheel set, comprising a plurality of wheels, a front wheel, and a rear wheel, and the plurality of wheels, the front wheel, and the rear wheel being pivoted on the side plates; one or more one-way roll stop devices, comprising a gearwheel and a pawl assembly, the gearwheel securing on the side of the front wheel or the rear wheel, the pawl assembly securing on the side plate, and the gearwheel and the pawl assembly corresponding to positions of each other; and one or more cushions, one end thereof being adapted on the side plate corresponding to the front wheel or the rear wheel, and the other end thereof connecting to the front wheel or the rear wheel and the gearwheel through a screw bolt assembly; wherein when the base is pressed, the cushion is compressed and drives the gearwheel to contact with the pawl assembly for stopping the front wheel or the rear wheel from rolling one-wayly.
 2. The improved structure of inline skates of claim 1, wherein the cushion includes a sliding block and sleeve assembly, a spring, and an adjustment shaft, the sliding block and sleeve assembly connecting with the front wheel or the rear wheel and the gearwheel through the screw and bolt assembly, the sliding block and sleeve assembly including a sleeve with a trench adapted for accommodating the spring and the adjustment shaft, and the top end of the adjustment shaft securing at the bottom of the connection plate.
 3. The improved structure of inline skates of claim 2, wherein the side plate connects pivotally with the front wheel or the rear wheel through a long pivotal bore, the sliding block and sleeve assembly further including a sliding block, the sliding block being a long block corresponding to the long pivotal bore with a shorter length, and the sliding block being able to inset in the long pivotal bore.
 4. The improved structure of inline skates of claim 2, wherein the adjustment shaft has threads thereon with one or more nuts, and the spring is confined between the trench and the nuts for adjusting the compression force of the spring.
 5. An improved structure of inline skates, comprising: a boot; a base, securing at the bottom of the boot, comprising one or more connection plates, and two side plates being adapted on both sides of the bottom of the connection plate, respectively with a plurality of pivotal holes thereon; a wheel set, comprising a plurality of wheels and a front wheel, the plurality of wheels being pivoted on the side plates, and the front wheel connecting with the plurality of wheels through a front side plate; one or more one-way roll stop devices, comprising a gearwheel and a pawl assembly, the gearwheel securing on the side of the front wheel, the pawl assembly securing on the side plate, and the gearwheel and the pawl assembly corresponding to positions of each other; and one or more cushions, one end thereof being adapted on the side plate corresponding to the front wheel, and the other end thereof connecting to the front wheel and the gearwheel through a screw bolt assembly; wherein when the base is pressed, the cushion is compressed and drives the gearwheel to contact with the pawl assembly for stopping the front wheel from rolling one-wayly.
 6. An improved structure of inline skates, comprising: a boot; a base, securing at the bottom of the boot, comprising one or more connection plates, and two side plates being adapted on both sides of the bottom of the connection plate, respectively with a plurality of pivotal holes thereon; a wheel set, comprising a plurality of wheels and a front wheel, the plurality of wheels being pivoted on the side plates, and the front wheel connecting with the plurality of wheels through a front side plate; one or more one-way roll stop devices, comprising a side gearwheel and a side pawl assembly, the side gearwheel securing inside of the front wheel, the side pawl assembly securing on the front side plate, and the side gearwheel and the side pawl assembly corresponding to positions of each other; one or more cushions, one end thereof being adapted on the side plate corresponding to the front wheel, and the other end thereof connecting to the front wheel, the front side plate, and the side gearwheel through a screw bolt assembly; and one or more driving apparatus, adapted on the side plate; wherein when the base is pressed downwards, the cushion is compressed and drives the driving apparatus to press the side pawl assembly to occlude the side gearwheel for stopping the front wheel from rolling one-wayly.
 7. The improved structure of inline skates of claim 6, wherein the driving apparatus has a contact inclined plane.
 8. An improved structure of inline skates, comprising: a boot; a base, securing at the bottom of the boot; a wheel set, comprising a plurality of wheels and a front wheel; one or more cushions, connecting to the front wheel and the base; and one or more one-way roll stop devices, being adapted at the location corresponding to the front wheel, and by accompanying the cushion making the one-way roll stop device in an occlusion and cease-rolling status or a free-sliding and maintain-rolling status; wherein when the base is pressed while the front wheel rolling backwards, the cushion is compressed and drives the one-way roll stop device for stopping the front wheel from rolling one-wayly. 